Module de.haumacher.msgbuf

Package de.haumacher.msgbuf.graph

Class DefaultScope

java.lang.Object

de.haumacher.msgbuf.graph.DefaultScope

All Implemented Interfaces:

Scope, ScopeMixin, Listener

public class DefaultScope
extends Object
implements Listener, ScopeMixin

The default Scope of an AbstractSharedGraphNode.

After adding this instance as listener to a node, the node is observed for changes. Changes can be externalized to a patch and transmitted over network to another DefaultScope containing a corresponding instance of the node. There, the patch an be applied bringing both shared object graphs in sync.

Nested Class Summary

Nested classes/interfaces inherited from interface de.haumacher.msgbuf.observer.Listener

Listener.MultiplexListener

Field Summary

Fields inherited from interface de.haumacher.msgbuf.observer.Listener

NONE

Constructor Summary

Constructors

Constructor	Description
DefaultScope(int totalParticipants, int participantId)	Creates a DefaultScope.

Method Summary

Modifier and Type	Method	Description
void	afterRemove(Observable obj, String property, int index, Object element)	Informs this Listener that an element was removed from a repeated property with the given name.
void	applyChanges(JsonReader json)	Applies changes read from the given JsonReader.
void	beforeAdd(Observable obj, String property, int index, Object element)	Informs this Listener that an element will be added to the repeated property with the given name.
protected void	beforeChange()	Hook called before the first change is recorded.
void	beforeSet(Observable obj, String property, Object value)	Informs this Listener that the value of the given property is to be modified.
void	createPatch(JsonWriter json)	Exports recorded changes to the given JsonWriter.
void	dropChanges()	Removes all recorded changes.
void	enter(SharedGraphNode node, int id)	Assigns the given ID to the given node.
Set<SharedGraphNode>	getDirty()	The set of nodes updated after the last sync.
boolean	hasChanges()	Checks whether there are changes to create a patch.
int	id(SharedGraphNode node)	Looks up the ID of the given node in this Scope.
Map<Object,SharedGraphNode>	index()	The index implementation associating object with IDs.
void	initId(SharedGraphNode node, int id)	Assigns the given ID to the given node.
static DefaultScope	newClientInstance()	Creates a DefaultScope for the client , where the graph is only shared between two participants, the client and the server.
int	newId()	Creates a fresh ID.
static DefaultScope	newServerInstance()	Creates a DefaultScope for the server, where the graph is only shared between two participants, the client and the server.
void	readData(SharedGraphNode node, int id, JsonReader in)	Reads object data of the given node and assigns the given ID to this node.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface de.haumacher.msgbuf.observer.Listener

afterChanged, afterRemove, beforeAdd

Methods inherited from interface de.haumacher.msgbuf.graph.ScopeMixin

resolveOrFail, writeRefOrData

Constructor Detail

DefaultScope

public DefaultScope(int totalParticipants,
                    int participantId)

Creates a DefaultScope.

Parameters:

totalParticipants - The total number of participants operating on the shared graph.

participantId - The ID of this participant.

Method Detail

newServerInstance

public static DefaultScope newServerInstance()

Creates a DefaultScope for the server, where the graph is only shared between two participants, the client and the server.

newClientInstance

public static DefaultScope newClientInstance()

Creates a DefaultScope for the client , where the graph is only shared between two participants, the client and the server.

beforeSet

public void beforeSet(Observable obj,
                      String property,
                      Object value)

Description copied from interface: Listener

Informs this Listener that the value of the given property is to be modified.

Specified by:

beforeSet in interface Listener

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

value - The new value that is being set to the given property.

beforeAdd

public void beforeAdd(Observable obj,
                      String property,
                      int index,
                      Object element)

Description copied from interface: Listener

Informs this Listener that an element will be added to the repeated property with the given name.

Specified by:

beforeAdd in interface Listener

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

index - The index where the new element will be added if the property is ordered, -1 otherwise.

element - The new element that is being added to the given property.

afterRemove

public void afterRemove(Observable obj,
                        String property,
                        int index,
                        Object element)

Description copied from interface: Listener

Informs this Listener that an element was removed from a repeated property with the given name.

Specified by:

afterRemove in interface Listener

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

index - The index where the element was removed if the property is ordered, -1 otherwise.

element - The element that was removed from the given property.

hasChanges

public boolean hasChanges()

Checks whether there are changes to create a patch.

dropChanges

public void dropChanges()

Removes all recorded changes.

getDirty

public Set<SharedGraphNode> getDirty()

The set of nodes updated after the last sync.

createPatch

public void createPatch(JsonWriter json)
                 throws IOException

Exports recorded changes to the given JsonWriter.

The recored changes are reset when this method completes.

The patch is a list containing an entry for each command. Each entry is a list with the command configuration at position 0 followed by optional additional arguments for the command.

Throws:

IOException

See Also:

applyChanges(JsonReader), hasChanges()

applyChanges

public void applyChanges(JsonReader json)
                  throws IOException

Applies changes read from the given JsonReader.

It is expected that the patch has the format as in createPatch(JsonWriter).

Throws:

IOException

See Also:

createPatch(JsonWriter)

enter

public void enter(SharedGraphNode node,
                  int id)

Description copied from interface: ScopeMixin

Assigns the given ID to the given node.

Specified by:

enter in interface ScopeMixin

readData

public void readData(SharedGraphNode node,
                     int id,
                     JsonReader in)
              throws IOException

Description copied from interface: Scope

Reads object data of the given node and assigns the given ID to this node.

Specified by:

readData in interface Scope

Specified by:

readData in interface ScopeMixin

Parameters:

node - The node to read data for.

id - The ID to assign ot the given node.

Throws:

IOException

beforeChange

protected void beforeChange()

Hook called before the first change is recorded.

The method is only called once during two synchronization cycles.

id

public int id(SharedGraphNode node)

Description copied from interface: ScopeMixin

Looks up the ID of the given node in this Scope.

Specified by:

id in interface ScopeMixin

See Also:

ScopeMixin.initId(SharedGraphNode, int)

initId

public void initId(SharedGraphNode node,
                   int id)

Description copied from interface: ScopeMixin

Assigns the given ID to the given node.

Specified by:

initId in interface ScopeMixin

See Also:

ScopeMixin.id(SharedGraphNode)

newId

public int newId()

Description copied from interface: ScopeMixin

Creates a fresh ID.

Specified by:

newId in interface ScopeMixin

index

public Map<Object,SharedGraphNode> index()

Description copied from interface: ScopeMixin

The index implementation associating object with IDs.

Specified by:

index in interface ScopeMixin